Tire pressure monitoring systems (TPMS) are used to monitor conditions within and surrounding vehicle tires. Parameters typically monitored include local temperature and pressure information. Many TPMS comprise tire-based sensors and other components that monitor and then transmit the local information via radio signals to a central receiver in another part of the vehicle. Power is supplied to the tire-based systems by local batteries, energy harvesters or scavengers, or other means.
Traditional TPMS are passive: the systems monitor one or more vehicle tires and optionally the ambient environment but do not interact with or provide feedback to the tires to actively adjust or compensate for sensed conditions. A driver may therefore be automatically notified of a condition, but any necessary or desired adjustment must be manually accomplished. For example, if snow or ice or hazardous driving conditions are detected, a driver may alter his or her driving behavior, such as by slowing down and judiciously applying the brakes, or by changing to winter or snow tires at the next opportunity. Problems may still result, however, if a driver makes insufficient or incorrect driving behavior alterations. Further, frequent changing of tires to conform to various driving and road conditions is impractical and expensive.